The Eiffel Tower will go dark at 8 p.m. local time on Wednesday to honor the residents of Aleppo, the Syrian City that has been recaptured by pro-government groups. Paris mayor Anne Hidalgo tweeted her support early Wednesday morning.

"We hope that this symbolic measure, on a monument that is known around the world, will show the international community once more the urgent need to act," she told Europe 1.

Pro-government forces have launched a ferocious assault on Aleppo's few remaining opposition-held neighborhoods, trapping thousands of civilians under unrelenting heavy fire. There are unconfirmed reports that government forces are killing civilians.

This week, European Union foreign policy chief Federica Mogherini appealed on the Syrian government and Russia to do their utmost to spare civilians as they prepared to capture the last rebel holdouts in Aleppo.

Mogherini said in a statement on Wednesday that "the priority now, in these hours, is to protect civilians, guarantee them safe and monitored transit to a place of safety."She added that "this is particularly the responsibility of the Syrian government and its allies." Mogherini also warned that "those who perpetrate war crimes will be held accountable."